Holding device for printing-plates



J. C. MAST.

HOLDING DEVICE FOR PRINTING PLATES.

APPLICATION FILED JULY 30, I919.

Patented June 15, 1920.

UNITED STATES JOHN c. MAST, or GLENARM, MARYLAND, Assieivoa TO 13. X. noorna COMPANY me, or GLENARM, MARYLAND, A CORPORATION or MARYLAND.

HOLDING DEVICE FOR PRINTING-PLATES.

Specification of Letters Patent. Patented June 15, 1926.

Application filed July 30, 1919. Serial No. 314,329.

To all whom it may concern:

Be it known that 1, JOHN C. MAST, a citizen of the United States, residing at Glenarm, in the county of Baltimore and State justable on the body into and out of engagement with the printing plate, and provided with means for applying a firm and yielding pressure to the plate in order that the plate may be securely clamped without injury to its edges.

In the accompanying drawing, which illustrates the invention, 7

Figure 1 is a top plan view of the plateholding device, showing the same secured to the base and engaging a printing plate;

Fig. 2 is a perspective view of the plateholding device;

Fig. 3 is a central, vertical, longitudinal section through the device;

Fig. 4 is a section on the line 4-4 of Fig. 3, a portion of the grooved base being shown in dotted lines; and

Fig. 5 is a perspective view of the springs for applying a yielding pressure to the clamping member.

Referring to the drawing, A' indicates a base for holding printing plates, said base being provided with parallel T-shaped grooves a; B indicates a printing plate and C indicates the plate-holding device of my invention. This device comprises a metal body 0 and a clamping member a, which is adjustable on the body. The body is H- shaped in cross section at one end, this portion comprising a web 1, adapted to fit within the narrow part of one of the grooves a, and two heads, 2 and 3, the former adapted to engage the under-cut portion of the groove and the latter adapted to rest upon the top of the base. An inte ral bar 4, rectangular in cross section an of less width than the web, projects from the web and 4 and extend below it, as shown. Studs 7 and 8 extend between the webs 6, below the bar 4, and leaf springs 9 and 10 are interposed between s'aid studs and the bar 4'for the purpose of holding the head 5 firmly but yieldingly against the bar 4. As shown, the spring 9 has one end bent around the stud 7 and the spring extends over said stud, thence below and around the'stud 8 and the free end 9 of the spring bears against the underside of the bar 4. The spring 10 is similarly formed but reversely arranged, one end of the latter spring bearing upon the stud. 8,

"thence passing beneath and around the stud 7, and its free end 1O bears against the underside of the bar 4. The bar 4 is formed with a V-shaped notch 11=in its upper side,

For the purpose of locking the holding device in the grooves of the printing bed, the body of the device is formed with a transverse opening 13 in its web and a short cylindrical block 14, slidable within said opening, is provided with a V-shaped notch 15, adapted to be engaged by a set screw 16, having a beveled endfor engaging the faces of the notch.

In operation the device is attached to :1 base by sliding it into one of the grooves, the head 2 lying within the under-cut portion of the groove, and the head 3 resting upon the base. The device is then moved forward to a point adjacent the printing plate and by turning the screw 16, the mem ber 14 is forced against one side of the groove and the device is thereby locked to the base. The adjusting screw 12 is then turned and the clamping member 0 is thereby forced forward and its beveled face 17 is thereby extended over and forced against the edge of the printing plate with a yield ing pressure, the springs 9 and 10 permitting the head to yield in an upward direction, thus avoiding injury to the edge of the plate which might occur if the clamping member were forced against the edge of the plate without any provision for permitting the member to yield.

\Vhat I claim is: 1. A device for clamping printing plates to grooved bases comprising a body having a part adapted to fit the groove and having a guide bar adapted to extend longitudinally in the groove, a clamping member in sliding engagement with said bar, said member comprising a head adapted to engage the printing plate, means for yieldingly pressing said member against the bar, Ineans for forcing said member forward on the bar, and means for locking said device to the base.

- 2. A device for clamping printing plates under side of the bar for yieldingly pressing said head against the bar, means for fore-- ing said member forward on the bar, and

means for locking said device to the base.

3. A device for clamping printing plates to grooved bases comprising a body having a part adapted to fit the groove and having a guide bar adapted to extend longitudinally in the groove, a clamping member in sliding engagement with said bar, said to grooved bases comprising a body having a part adapted to fit the groove and having an integral guide bar adapted to extend longitudinally in the groove, said bar having an inclined surface on its upper side, a clamping member slidable on said bar, an adjusting screw in-said member adapted to engage said surface,.and means for yieldingly pressing said member downwardly against the bar.

- In testimony whereof I affix my signature.

JOHN C. MAST.

4. A device for clamping printing plates 

